If she eats a lot of bread (or anything made with regular American wheat) her thyroid problems could easily have been exacerbated by the bromine that's used to treat flour. Bromine is similar to iodine in that it's a halide, and the thyroid readily absorbs it in the absence of iodine. The problem is that bromine cannot be used to make some of the hormones produced by the thyroid, and it has a much higher toxicity than iodine which tends to cascade into liver problems.